SUMMARY

Our understanding of the seismicity of continental interiors, far from plate margins, relies on the ability to account for behaviours across a broad range of time and spatial scales. Deformation rates around seismic faults range from the slip-on-fault during earthquakes to the long-term viscous deformation of surrounding lithosphere, thereby presenting a challenge to modelling techniques. The aim of this study was to test a new method to simulate seismic faults using a continuum approach, reconciling the deformation of viscoelastoplastic lithospheres over geological timescales. A von Mises yield criterion is adopted as a proxy for the frictional shear strength of a fault. In the elastoplastic fault models a rapid change in strength occurs after plastic yielding, to achieve stress–strain equilibrium, when the coseismic slip and slip velocity from the strain-rate response and size of the fault are calculated. The cumulative step-function shape of the slip and temporally partitioned slip velocity of the fault demonstrated self-consistent discrete fault motion. The implementation of elastoplastic faults successfully reproduced the conceptual models of seismic recurrence, that is strictly periodic and time- and slip-predictable. Elastoplastic faults that include a slip velocity strengthening and weakening with reduction of the time-step size during the slip stage generated yield patterns of coseismic stress changes in surrounding areas, which were similar to those calculated from actual earthquakes. A test of fault interaction captured the migration of stress between two faults under different spatial arrangements, reproducing realistic behaviours across time and spatial scales of faults in continental interiors.

中文翻译：

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板内环境中弹塑性断层的自洽粘滑反复性：拉格朗日固体力学方法

概要

我们对大陆内部地震活动的了解，远非板缘，而是依赖于在广泛的时间和空间范围内解释行为的能力。地震断层周围的变形率范围从地震发生时的滑移到周围岩石圈的长期粘性变形，因此对建模技术提出了挑战。这项研究的目的是测试一种使用连续介质方法模拟地震断层的新方法，以协调地质时期内粘弹塑性岩石圈的变形。采用冯·米塞斯屈服准则作为断层摩擦剪切强度的代名词。在弹塑性断层模型中，塑性屈服后强度发生快速变化，以实现应力-应变平衡，当从应变率响应和断层尺寸计算出同震滑动和滑动速度时。滑移的累积阶跃函数形状和故障的时间划分滑移速度表现出自洽的离散断层运动。弹塑性断层的实施成功地再现了地震复发的概念模型，该模型严格地是周期性的并且是时间和滑动可预测的。滑移阶段随着时间步长的减小而滑动速度增强和减弱的弹塑性断层，在周围区域产生了同震应力变化的屈服模式，这与从实际地震中得出的相似。断层相互作用的测试记录了在不同空间布置下两个断层之间应力的迁移，